U.S. import prices increased solidly in May, boosted by a surge in the cost of petroleum products and food, but underlying imported inflation remained benign.

The Labor Department said on Thursday import prices increased 0.6 percent last month. Data for April was revised to show import prices rising 0.6 percent instead of the previously reported 0.3 percent gain.

Economists polled by Reuters had forecast import prices rising 0.5 percent in May. In the 12 months through May, import prices increased 4.3 percent, the biggest rise since February 2017, after advancing 3.6 percent in April.

Last month, prices for imported petroleum jumped 5.9 percent, the largest gain since November 2017 after rising 4.4 percent in April. Excluding petroleum, import prices edged up 0.1 percent in May, matching April’s gain. Import prices excluding petroleum rose 1.8 percent in the 12 months through May. The report also showed export prices rose 0.6 percent in May, lifted by an increase in the prices of wheat, corns, and soybeans. That followed a similar gain in April. Export prices increased 4.9 percent on a year-on-year basis, the biggest rise since October 2011, after advancing 3.7 percent in April